The use and demand of alternatives for synthetic food colorants has been increasing due to possible health concerns and consumer demand. However, natural food colorants have not been able to achieve the same color characteristics as their synthetic counterparts, for example, FD&C Blue No. 1. The lack of a suitable natural blue colorant has also made the development of a desirable natural green hue, from a combination of natural blue and yellow colorants, difficult.
Anthocyanins are known as natural food colorants responsible for reds and blues of fruits and vegetables. It is known in the art that anthocyanin-containing juices and extracts generally exhibit red hues at low pH and the hue shifts towards purple as pH increases. International Patent Publication No. WO 2014/152417 discloses the isolation of fractions of anthocyanin molecules from vegetable and fruit extracts, including red cabbage, at select pHs to provide different color characteristics than those provided by the source vegetable or fruit.
As a class, anthocyanins encompass a large number of structurally diverse compounds based on differences in primary structure, glycosylation and acylation patterns. Anthocyanins comprise an anthocyanidin esterified to one or more sugar molecules. Examples of sugar molecules found in anthocyanin structures are arabinose, galactose, glucose, rhamnose, rutinose, sambubiose, sophorose and xylose. An anthocyanin may be substituted with hydrogen, hydroxyl, and/or methoxyl groups at various positions. Anthocyanins can also be acylated, where they may have one or more molecules esterified to the sugar molecules at the 2-, 3-, 4- and/or 6-position of a monosaccharide.
The currently available blue colorant compositions that are produced from natural sources have not been satisfactory for use in food products. For example, natural blue colorant compositions have been shown to be unstable and undergo color shifts when incorporated into a food product. Therefore, there remains a need for a natural blue anthocyanin colorant composition that provides the similar color characteristics and stability as a synthetic counterpart, such as FD&C Blue No. 1.